Portable internal-combustion



Feb. 14, 1956 A. N. WAMPACH PORTABLE INTERNAL-COMBUSTION PERCUSSIVETOOLS Filed Oct. 7, 1952 INVENTOR. A\ mp: Nmehua wameqgk BY." M g s. um

United States Patent PORTABLE INTERNAL-COMBUSTION PERCUSSIVE TOOLSAloyse Nicolas Wampach, Luxemburg, Luxemburg Application October 7,1952, Serial No. 313,420

Claims priority, application Luxemburg October 12, 1951 1 Claim. (Cl.123-7) This invention relates to portable internal combustion percussivetools and it has for its object a percussive tool of this type which isan improvement on the type in present use and is adapted for use notonly as a concretebreaker, a ram or like tool, but also as a rock-drill.

In portable internal combustion tools (concrete-breaking hammers, rams,rock-drills and the like) the return of the working piston gives rise todifliculties. Up to now, this return was due to the action of eithercompressed air or of exhaust gas, alone or mixed with air constituting acushion, or again, most often, by springs in compression, of more orless length, acting underneath the working piston.

This latter solution of the problem, although apparently quite simple,has nevertheless the great disadvantage that these compression springsdo not resist in the course of time the continual fatigue due to nearly2000 strokes per minute with such a relatively long piston stroke, sothat the springs lose promptly their resilience and fractures takeplace. According to my present invention, I provide a portable internalcombustion percussive tool adapted to serve as a concrete breaker, aram, or the like and also as a rock-drill, characterised in that thereturn of the working piston is caused by a tension spring housed in asteel tube disposed above the piston.

Referring to the accompanying drawing, which represents a preferredembodiment of the invention, given in the way of example:

Fig. 1 is a sectional elevation;

Fig. 2 is a plan view;

Fig. 3 is a sectional elevational of an alternative detail.

In the drawing, 1 is the working piston, the return of which takes placeby means of a tension spring 2, housed in a tube 3, where it issheltered from the heat of the explosion gases. The tube 3 is firmlyheld in a blind bore axially of the piston; it passes through thecombustion chamber 4 and through the head 5' of the cylinder 5,providing with a fluid-tight stufiing gland 6.

In accordance with the invention, the tube 3 is tightly held in the boreof the piston 1 in which it is secured by a pin 7 to which is anchoredone end of the traction spring 2. One end of this pin is provided with aprojection 8 adapted to engage a longitudinal groove in the cylinder 5so as to prevent any rotation of the piston. This arrangement does notonly ensure a solid connection between the tube 3 and the piston, but italso allows the use of a tension spring 2 as long as may be necessary topractically eliminate any risk of rupture. This spring is anchored atthe top to a cover 14 resting on the guiding rods 11.

2,734,488 Patented Feb. 14, 1956 The tube 3 serves at the same time as apushing member for starting. With its help, the piston 1 is initiallymoved for starting the tool, in a simple and handy manner by the twohandles 9, connected to a middle member 10 housed in such a way that itslides between the guiding rods 11. This middle member 10 is connectedeither to the tube 3, to be put in motion, by means of the claws 12, orelse to the head 5 of the cylinder by means of the crank levers 13, ifit is desired to cause the tool to work continuously once the piston 1has been started.

It is advantageous to arrange the suspension of the spring 2 to thecover 14 so that it is adjustable, for example by a threaded member 33(Fig. 3), so as to be able to give an optimum tension to this spring. Itis then possible to suitably control both the compression of the gaseousmixture and the energy of impact of the strokes. V

In order to utilize the tool for work involving rockdrilling and thelike, it is required to impart to the cutter a rotary motion at eachstroke of the percussive tool, the cutter acting then as a drill. Tothis end, a rotary device is provided, adapted to automatically rotatethe drill and blowing the dust produced by the cutter while the workproceeds.

According to the invention, a guiding rotative sleeve 15, carries thedrill, which is preferably of hexagonal steel with a bore 17 throughoutits length. This sleeve 15 is connected by notches 19 to another sleeve18, provided on its periphery with teeth 20 (Fig. 2) constituting aratchet wheel engaged by a pawl 21 acted by the tension spring 210. Thispawl is housed in the body 22, one of the front faces of whichcommunicates with the combustion chamber by means of the passage 23,while the other is controlled by the spring 24.

With such an arrangement, the explosion in the chamber 4 has also anelfect on the piston 22 and thrusts it forward, compressing the spring24; the toothed sleeve 18 (Fig. 1) rotates through an anglecorresponding to one tooth 20, and with it the sleeve 15 andconsequently the drill 16. When the burnt gases escape at the end of apower stroke, the piston 22 is also unloaded and the spring 24 brings itback in the position shown in the Fig. 2.

The tool effecting about 2000 strokes per minute, and the ratchet wheelhaving about 20 teeth, the drill will make about turns per minute. Theregulating stop 34 allows the length of the stroke of the piston 22 tobe adjusted, and consequently also the speed of the angular displacementof the drill.

In accordance with the invention, the blowing air enters the device bythe opening 25. It passes along the bore 26 which is controlled by thedistributor 27 which is maintained by the spring 28 in the positionshown in Fig. 2, closing the passage 26. It is only when the surface ofthe upper face of the distributor 27 has just been subjected to thepressure caused by the explosion in the chamber 4, exerted through thevertical bores 23 and the communication passage 29, that the distributor27 is pushed downwards and an annular recessed portion 30 thereon opensthe passage 26. The blowing air then passes from the inlet orificethrough the passage 26 in the annular recess 31 and thence by the bores32 and 17 on the bottom of the hole being bored where it cleans thecutting edge of the drill 16. According to the invention, the blowingtakes place therefore by gusts at each stroke. A needle valve 35regulates the section of the passage 26.

What I claim is: t

In a portable internal combustion percussive device having an operatingtool, in combination, an elongated housing member defining a lowercylinder chamber and an upper combustion chamber; piston means arrangedreciprocably in said housing member with said lower cylinder chamberlocated under and said upper combustion chamber located above saidpiston means, said piston means serving for actuating the operatingtool; tubular means located above and secured to said piston means; andresilient means in said tubular means and connected to said piston meanspermanently urging said piston 5 means toward said combustion chamber.

References Cited in the file of this patent UNITED STATES PATENTS1,755,361 Pfluger et al Apr. 22, 1930 2,125,013 Charles July 26, 19382,225,531 Charles Dec. 17, 1940

